You might consider the way some bench shooters have been doing it since before cartridges were invented, they use a linin paper patch cut in the shape of a cross so the edges fit together closely. If you watch at Friendship when they have the bench rest championship match at a 1000 meters you can see how good it works, there are a number of different bullets even a hybredbullets that have 2 different hardnesses of lead in them. Normally a soft lead bullet is used with a paper patch I dont know if a jacketed bullet can be made to work but the possability is there; you might even try a cloth or teflon patch cut that way. Lee